A good yellow dress has a certain weight to it even before you try it on, something a bit more substantial than you expect from a colour that reads so light. You hold it up against yourself in the mirror first, which you don't always bother with for navy or black, because yellow needs that quick check against your own skin before you commit. The good ones don't look flimsy on the hanger. They look like they mean it.
What yellow doesn't want near it is a loud bag or a print that's trying to have its own conversation. I learned this the hard way with a floral clutch that had every colour in it except the one that mattered, and the whole outfit looked like it had been assembled by committee. Keep the rest quiet, tan or white or a plain sandal, and let the dress do the talking. As for when it works, this is a fair weather colour in every sense, it wants sun on it, or at least the promise of some, so it earns its place at daytime weddings, garden parties, the sort of lunch that runs on for three hours because nobody wants to be the first to leave. It looks wrong under grey skies and artificial light in a way that navy never does, so I wouldn't reach for it for a winter work do, it just sits there looking confused about why it's there. A well made one and a disappointing one usually reveal themselves in the fabric before anything else. Cheap yellow has a slight plasticky sheen under certain lights, almost fluorescent, and it clings in the wrong places and creases if you so much as sit down for ten minutes. The better ones have a cotton or viscose with enough body to skim rather than stick, and they hang with a bit of movement instead of static cling the second you walk past anything synthetic. Check the seams too, yellow shows a bad hem or a pulled thread far more honestly than darker shades do, there's nowhere for sloppy construction to hide. Lining matters more than you'd think, because pale yellow can go slightly see through in strong daylight, and you do not want to find that out standing in a marquee doorway with the sun behind you.
I've got one in a cotton poplin that's done two different weddings eighteen months apart, and nobody has said a word, because it still looks sharp rather than tired. If you find the right version, it tends to stay in rotation longer than you'd expect from something so specific.